.beta.-Ketocarboximides of .alpha.,.beta.-unsaturated amides, such as, for example, N-acetoacetyl acrylamide, are functionalized acrylamide monomers which can be copolymerized with other acrylate or acrylamide monomers to provide crosslinkable thermoset films. It would be desirable to prepare N-acetoacetyl acrylamide directly from diketene and acrylamide. The only process known for this direct conversion involves the reaction of diketene with acrylamide in the presence of a stoichiometric amount of trimethylsilyl chloride/sodium bromide (MeCN,12h) to afford a 77% yield of N-acetoacetyl acrylamide. Unfortunately, this procedure for preparing N-acetoacetyl acrylamide directly from acrylamide and diketene is expensive and impractical for large-scale preparations. Other attempts to directly acetoacetylate acrylamide with diketene have not been successful.
An alternate process for the preparation of .beta.-ketocarboximides from amides has been reported in the literature, involving reaction of amides with the diketene-acetone adduct, 2,2,6-trimethyl-4H-1,3-dioxin-4-one (TKD). However, low yields (&lt;45%) are reported when this reaction of TKD with acrylamide is run neat according to this reported procedure, with even lower yields reported (.about.20%) when this reaction is carried out in xylene as solvent.
There is, therefore, a need for an improved process for synthesizing .beta.-ketocarboximides of .alpha.,.beta.-unsaturated amides wherein the desired acrylamide is obtained in high yield and product recovery is readily accomplished.